to make it easier for others; and to aid my critismsm..
these two i think are the best to start with; you mentioned in one of the comments that you've been told you need to work on your shading. let me start by saying that i agree; your basic technique is good, but the light has to come from somewhere; a definite direction; best to use a single source to begin with
(I will post a pic explaining better when I'm on my own PC again
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your basic technique is good, and you are improving, start looking closer at lighting in images and body proportions, try copying to start with, until you get a good feel for these things (but if you post up on DA, make sure to cite the original artist; DA has a wonderful amount of stock artists for this kind of thing
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keep it up! ^^